This invention relates generally to the field of mailing machines, and more particularly to guiding and feeding a mailpiece past a printing station.
Generally, a mailpiece transport on a mailing machine transports envelopes and other mailpieces along a feed path so that various functions may be performed on the mailpiece at different locations along the feed path. For example, at one location along the feed path the mailpiece may be weighed, at another location the mailpiece may be sealed, and at a further location an indicium for postage may be applied to the mailpiece. Drive rollers and/or drive belts may be employed to contact the mailpiece to propel the mailpiece along the feed path.
When a drive belt is employed, structures must be provided to keep the mailpiece in contact with the drive belt. In conventional arrangements, spring-loaded pivot arms are provided along the drive belt. At a free end of each pivot arm, a roller is mounted to contact the mailpiece as the mailpiece is driven by the drive belt and to apply a force to the mailpiece so that the mailpiece is maintained in frictional contact with the drive belt. To prevent the drive belt from deflecting due to the force imparted by the pivot arm, a backup roller is provided behind the drive belt at each point where the belt is in contact with a roller mounted on a pivot arm. Each pair of rollers formed of a pivot arm roller and the corresponding backup roller constitutes a spring-loaded nip through which the mailpiece is fed by the drive belt.
A common requirement for mailing machines is that they be capable of handling mailpieces of varying sizes and thicknesses. For example, a mailing machine may be required to process mailpieces that vary in thickness from 0.007 inch to 0.75 inch. The mailpieces may also vary in length over a considerable range. The degree of compliance provided for the above-described pivot arms, and the shape of the arms, customarily take into account the varying thicknesses of the mailpieces to be processed. To prevent mailpieces from skewing while being transported, the spring-loaded nips may be set at a spacing relative to each other such that the maximum distance between two adjacent nips is less than half of the length of the shortest mailpiece to be processed by the mailing machine. As a result, a mailpiece is generally held between at least two nips while being driven by the drive belt.
In some mailing machines, mailpieces are driven past a printing station by a drive belt. At the printing station a postage indicium may be printed on the mailpiece. Ink jet printing technology is commonly employed for printing of postal indicia. Some current practices call for postage indicia to include printing of a two-dimensional barcode that indicates data relating to the dispensing of the postage for the mailpiece. Because the barcode represents part of the security system for dispensing the postage, it is necessary that the printing occur with a high degree of reliability and fidelity so that the barcode can be successfully read to verify that the postage was properly dispensed. However, if the motion of the mailpiece is disturbed while printing of the postal indicium is occurring, the surface of the mailpiece on which the printing is taking place may be buckled or otherwise distorted. This may cause the printed image to be distorted, in which case the barcode may not be properly readable.
Therefore, it would be advantageous to provide apparatus and methods that minimize the possibility that the motion of a mailpiece is disturbed while an indicium is being printed on the mailpiece.
Accordingly, an improved apparatus and method for transporting a mailpiece along a feed path in a mailing machine is provided. The improved apparatus includes an endless belt that has a lower belt run that extends in a generally horizontal direction. The belt run is adapted to feed the mailpiece in a downstream direction. The apparatus also includes a plurality of pivot arms mounted in a sequence below the lower belt run. Each pivot arm has a respective roller mounted on a free end of the pivot arm. A respective bias mechanism is associated with each pivot arm to bias the pivot arm in an upward direction such that the roller contacts the lower belt run. The plurality of pivot arms includes a first pivot arm and a second pivot arm. The second pivot arm is positioned downstream from the first pivot arm and adjacent to the first pivot arm in the sequence of pivot arms. The first and second pivot arms are configured such that the first pivot arm actuates the second pivot arm in a downward direction when the first pivot arm is actuated in a downward direction by the mailpiece that is fed by the endless belt.
For example, the second pivot arm may be mounted on a free end of a third pivot arm that is mounted downstream from the first pivot arm. The second pivot arm may extend in a substantially horizontal and upstream direction from the free end of the third pivot arm toward the free end of the first pivot arm. The second pivot arm may include a lever that extends beyond a free end of the second pivot arm to contact a lower surface of the free end of the first pivot arm. The lever may include a ramp surface on which the lower surface of the free end of the first pivot arm rides while the first pivot arm downwardly actuates the second pivot arm. The second pivot arm and the roller mounted on the free end of the third pivot arm may both be mounted on a common shaft. The bias mechanism associated with the second pivot arm may include a coil spring held between the second pivot arm and the third pivot arm. The coil spring may be in contact with a lower surface of the lever. The first pivot arm may have an upstream-facing surface that has a convex profile and the third pivot arm may have an upstream-facing surface that has a concave profile.
In another aspect, an apparatus for processing a mailpiece includes a base and a feed mechanism mounted on the base. The feed mechanism feeds the mailpiece along a feed path in a downstream direction. The feed mechanism includes a first nip positioned at a first point along the feed path. The first nip is formed by a first upper roller and a first lower roller. The feed mechanism also includes a second nip positioned at a second point along the feed path that is downstream from the first nip. The second nip is formed by a second upper roller and a second lower roller. The feed mechanism further includes a pre-opening mechanism which opens the second nip in response to the mailpiece being fed through the first nip and before the mailpiece reaches the second nip.
In still another aspect, a roller assembly includes a primary arm which has a proximal end adapted to be mounted to a support. The primary arm also has a distal end that is opposite to the proximal end. The roller assembly also includes a primary roller mounted for rotation at the distal end of the primary arm. The roller assembly further includes a secondary arm which has a proximal end that is pivotally mounted to the distal end of the primary arm. Further, the roller assembly includes a secondary roller mounted for rotation on the secondary arm.
In yet another aspect, a method is provided for feeding a mailpiece along a feed path. The method includes feeding a mailpiece through a first nip, thereby opening the first nip. The method further includes opening a second nip downstream from the first nip in response to the opening of the first nip. The opening of the second nip occurs before the mailpiece reaches the second nip.
Therefore, it should now be apparent that the invention substantially achieves all the above aspects and advantages. Additional aspects and advantages of the invention will be set forth in the description that follows, and in part will be obvious from the description, or may be learned by practice of the invention. Various features and embodiments are further described in the following figures, description and claims.